<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<head>
<title>Source code</title>
<link rel="stylesheet" type="text/css" href="../../../../../stylesheet.css" title="Style">
</head>
<body>
<div class="sourceContainer">
<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: SnapshotVersion.html 939 2015-05-29 01:16:17Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.kv.mvcc;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.util.Collections;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.util.HashSet;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import java.util.Set;<a name="line.12"></a>
<span class="sourceLineNo">013</span><a name="line.13"></a>
<span class="sourceLineNo">014</span>import org.jsimpledb.kv.KVStore;<a name="line.14"></a>
<span class="sourceLineNo">015</span><a name="line.15"></a>
<span class="sourceLineNo">016</span>/**<a name="line.16"></a>
<span class="sourceLineNo">017</span> * Represents one {@link SnapshotKVDatabase} MVCC version.<a name="line.17"></a>
<span class="sourceLineNo">018</span> *<a name="line.18"></a>
<span class="sourceLineNo">019</span> * &lt;p&gt;<a name="line.19"></a>
<span class="sourceLineNo">020</span> * Information included:<a name="line.20"></a>
<span class="sourceLineNo">021</span> *  &lt;ul&gt;<a name="line.21"></a>
<span class="sourceLineNo">022</span> *  &lt;li&gt;MVCC version number&lt;/li&gt;<a name="line.22"></a>
<span class="sourceLineNo">023</span> *  &lt;li&gt;{@link KVStore} snapshot&lt;/li&gt;<a name="line.23"></a>
<span class="sourceLineNo">024</span> *  &lt;li&gt;Open transactions based on this version&lt;/li&gt;<a name="line.24"></a>
<span class="sourceLineNo">025</span> *  &lt;li&gt;The {@link Writes} of the transaction that was committed on this version, if any&lt;/li&gt;<a name="line.25"></a>
<span class="sourceLineNo">026</span> *  &lt;/ul&gt;<a name="line.26"></a>
<span class="sourceLineNo">027</span> */<a name="line.27"></a>
<span class="sourceLineNo">028</span>public class SnapshotVersion {<a name="line.28"></a>
<span class="sourceLineNo">029</span><a name="line.29"></a>
<span class="sourceLineNo">030</span>    private final long version;<a name="line.30"></a>
<span class="sourceLineNo">031</span>    private final KVStore snapshot;<a name="line.31"></a>
<span class="sourceLineNo">032</span>    private final HashSet&lt;SnapshotKVTransaction&gt; openTransactions = new HashSet&lt;&gt;(2);<a name="line.32"></a>
<span class="sourceLineNo">033</span><a name="line.33"></a>
<span class="sourceLineNo">034</span>    private Writes committedWrites;<a name="line.34"></a>
<span class="sourceLineNo">035</span><a name="line.35"></a>
<span class="sourceLineNo">036</span>    /**<a name="line.36"></a>
<span class="sourceLineNo">037</span>     * Constructor.<a name="line.37"></a>
<span class="sourceLineNo">038</span>     *<a name="line.38"></a>
<span class="sourceLineNo">039</span>     * @param version version number<a name="line.39"></a>
<span class="sourceLineNo">040</span>     * @param snapshot database snapshot<a name="line.40"></a>
<span class="sourceLineNo">041</span>     */<a name="line.41"></a>
<span class="sourceLineNo">042</span>    SnapshotVersion(long version, KVStore snapshot) {<a name="line.42"></a>
<span class="sourceLineNo">043</span>        this.version = version;<a name="line.43"></a>
<span class="sourceLineNo">044</span>        this.snapshot = snapshot;<a name="line.44"></a>
<span class="sourceLineNo">045</span>    }<a name="line.45"></a>
<span class="sourceLineNo">046</span><a name="line.46"></a>
<span class="sourceLineNo">047</span>    /**<a name="line.47"></a>
<span class="sourceLineNo">048</span>     * Get this instance's unique version number.<a name="line.48"></a>
<span class="sourceLineNo">049</span>     *<a name="line.49"></a>
<span class="sourceLineNo">050</span>     * @return MVCC version number<a name="line.50"></a>
<span class="sourceLineNo">051</span>     */<a name="line.51"></a>
<span class="sourceLineNo">052</span>    public long getVersion() {<a name="line.52"></a>
<span class="sourceLineNo">053</span>        return this.version;<a name="line.53"></a>
<span class="sourceLineNo">054</span>    }<a name="line.54"></a>
<span class="sourceLineNo">055</span><a name="line.55"></a>
<span class="sourceLineNo">056</span>    /**<a name="line.56"></a>
<span class="sourceLineNo">057</span>     * Get the {@link KVStore} view of this version's snapshot.<a name="line.57"></a>
<span class="sourceLineNo">058</span>     *<a name="line.58"></a>
<span class="sourceLineNo">059</span>     * @return unmodifiable {@link KVStore}<a name="line.59"></a>
<span class="sourceLineNo">060</span>     */<a name="line.60"></a>
<span class="sourceLineNo">061</span>    public KVStore getSnapshot() {<a name="line.61"></a>
<span class="sourceLineNo">062</span>        return this.snapshot;<a name="line.62"></a>
<span class="sourceLineNo">063</span>    }<a name="line.63"></a>
<span class="sourceLineNo">064</span><a name="line.64"></a>
<span class="sourceLineNo">065</span>    /**<a name="line.65"></a>
<span class="sourceLineNo">066</span>     * Get transactions based on this version's snapshot that are still open.<a name="line.66"></a>
<span class="sourceLineNo">067</span>     *<a name="line.67"></a>
<span class="sourceLineNo">068</span>     * @return immutable view of open transactions associated with this version<a name="line.68"></a>
<span class="sourceLineNo">069</span>     */<a name="line.69"></a>
<span class="sourceLineNo">070</span>    public Set&lt;SnapshotKVTransaction&gt; getOpenTransactions() {<a name="line.70"></a>
<span class="sourceLineNo">071</span>        return Collections.unmodifiableSet(this.openTransactions);<a name="line.71"></a>
<span class="sourceLineNo">072</span>    }<a name="line.72"></a>
<span class="sourceLineNo">073</span><a name="line.73"></a>
<span class="sourceLineNo">074</span>    /**<a name="line.74"></a>
<span class="sourceLineNo">075</span>     * Get the {@link Writes} of the transaction based on this version's snapshot that was eventually committed, if any.<a name="line.75"></a>
<span class="sourceLineNo">076</span>     *<a name="line.76"></a>
<span class="sourceLineNo">077</span>     * @return writes of the transaction committed on this version, or null if there is none<a name="line.77"></a>
<span class="sourceLineNo">078</span>     */<a name="line.78"></a>
<span class="sourceLineNo">079</span>    public Writes getCommittedWrites() {<a name="line.79"></a>
<span class="sourceLineNo">080</span>        return this.committedWrites;<a name="line.80"></a>
<span class="sourceLineNo">081</span>    }<a name="line.81"></a>
<span class="sourceLineNo">082</span><a name="line.82"></a>
<span class="sourceLineNo">083</span>// Package methods<a name="line.83"></a>
<span class="sourceLineNo">084</span><a name="line.84"></a>
<span class="sourceLineNo">085</span>    void addOpenTransaction(SnapshotKVTransaction tx) {<a name="line.85"></a>
<span class="sourceLineNo">086</span>        this.openTransactions.add(tx);<a name="line.86"></a>
<span class="sourceLineNo">087</span>    }<a name="line.87"></a>
<span class="sourceLineNo">088</span><a name="line.88"></a>
<span class="sourceLineNo">089</span>    void removeOpenTransaction(SnapshotKVTransaction tx) {<a name="line.89"></a>
<span class="sourceLineNo">090</span>        this.openTransactions.remove(tx);<a name="line.90"></a>
<span class="sourceLineNo">091</span>    }<a name="line.91"></a>
<span class="sourceLineNo">092</span><a name="line.92"></a>
<span class="sourceLineNo">093</span>    void setCommittedWrites(Writes committedWrites) {<a name="line.93"></a>
<span class="sourceLineNo">094</span>        this.committedWrites = committedWrites;<a name="line.94"></a>
<span class="sourceLineNo">095</span>    }<a name="line.95"></a>
<span class="sourceLineNo">096</span><a name="line.96"></a>
<span class="sourceLineNo">097</span>// Object<a name="line.97"></a>
<span class="sourceLineNo">098</span><a name="line.98"></a>
<span class="sourceLineNo">099</span>    @Override<a name="line.99"></a>
<span class="sourceLineNo">100</span>    public String toString() {<a name="line.100"></a>
<span class="sourceLineNo">101</span>        return this.getClass().getSimpleName()<a name="line.101"></a>
<span class="sourceLineNo">102</span>          + "[vers=" + this.version<a name="line.102"></a>
<span class="sourceLineNo">103</span>          + ",snapshot=" + this.snapshot<a name="line.103"></a>
<span class="sourceLineNo">104</span>          + (!this.openTransactions.isEmpty() ? ",openTx=" + this.openTransactions : "")<a name="line.104"></a>
<span class="sourceLineNo">105</span>          + (this.committedWrites != null ? ",writes=" + this.committedWrites : "")<a name="line.105"></a>
<span class="sourceLineNo">106</span>          + "]";<a name="line.106"></a>
<span class="sourceLineNo">107</span>    }<a name="line.107"></a>
<span class="sourceLineNo">108</span>}<a name="line.108"></a>
<span class="sourceLineNo">109</span><a name="line.109"></a>




























































</pre>
</div>
</body>
</html>
